The Blue Cross pet charity is targeting cold donors for the first time with a direct marketing campaign.
The Old Age Pets Appeal pack was sent last week to 48,000 prospective donors from lists sourced by HLB, sister company to pack designer WWAV Rapp Collins.
Recipients of the pack are being asked for cash donations of at least £15, to help find a home for abandoned animals around the Christmas period.
The pack tells the story of Millie, an elderly dog abandoned by her owners after they bought a new puppy.
Steve Goody, director of companion animal welfare at the charity, said: "This Christmas, Blue Cross Adoption Centres will be full of animals who haven't yet found new homes because of their age."
The charity will use the money to provide extra veterinary care for these old pets over the winter and eventually re-home them. It also sent the pack out to 130,000 existing donors.